1. Technical Field
The present invention relates generally to health-related symptoms and problems resulting from the use of video display terminals and related computer equipment. More particularly, the present invention is directed to a unique apparatus and method for assessing and quantifying the correct ergonomic position of a video display terminal.
2. Background Information
In the past 15 years, the number of individuals using computers has increased at a phenomenal rate. This growth can be attributed primarily to the development and widespread availability of personal or desk-top type computers equipped with video display terminals (VDTs). In fact, it is estimated that within the near future a majority of office workers will be using computers on a regular basis.
Although this increased use of computers is highly beneficial, it has also resulted in a variety of unfortunate side-effects. Often, these side-effects are related to various computer-induced disorders that result from the visual demands of regular and prolonged use of a computer equipped with a VDT. Symptoms often complained of include: headaches, near blurred vision, slowness in focusing (distance to near and back), double vision, eyestrain, glare sensitivity, eye irritation, and neck, back and shoulder pain.
Frequently, these and other symptoms are attributable to an improper arrangement of a computer operator's work environment. A computer operator's entire body posture is dictated by what he or she is viewing and, with a fixed element such as a VDT, the operator will typically position the body so that the eyes can see comfortably. If the operator must assume an uncomfortable position to properly see the VDT, many of the above problems can occur--especially in individuals who spend long periods of time working at a computer.
Consequently, the proper positioning and orientation of the computer and the video display terminal is extremely important to an operator's visual and physical health. Optimally, the VDT must be positioned so that it is comfortable both for the eyes and for the body. For instance, studies have shown that for most operators a VDT should be positioned ten (10) to twenty (20) degrees below the operator's line of sight. A VDT that is positioned improperly (high or low) can: cause eye irritation (often caused by a below-normal blink rate); stress the operator's accommodative system (i.e., a reduced amplitude of accommodation); and place physical stress on the operator's neck, back and/or shoulders.
In addition, an improper viewing distance between the operator and the VDT can also result in various computer-induced disorders. Although there can be a wide range of acceptable viewing distances depending on the particular type of screen being used and the type of tasks being performed, a viewing distance between twenty (20) to twenty-eight (28) inches is most common. If the distance is outside of this range, there could be undue stress on the operator's eyes and/or body position. Also, an improper viewing distance could indicate underlying visual problems, or could be contributing to other symptoms.
Whether a VDT is properly positioned is also highly dependent on the particular operator's visual acuity (i.e., ability to see detail). If an operator's visual acuity is inadequate when viewing the VDT, various visual symptoms can occur. Also, poor acuity can also cause the operator to make unnatural posture adjustments that can result in the various physiological problems associated with computer usage. Further, many computer operators have prescription lenses, such as bifocals or other multifocal lenses. Although these lenses are satisfactory for the majority of daily visual requirements, they may be entirely inappropriate for the viewing distances and viewing angles associated with computer and VDT usage.
The various computer-induced symptoms that result from an improper positioning of the computer VDT are of utmost concern. Such symptoms can greatly reduce a computer operator's productivity, and can potentially lead to more chronic health problems. Obviously, both computer operators and their employers have a need to identify and correct such problems, and more importantly, to prevent their occurrence in the first instance.
Fortunately, the underlying causes can often be corrected or prevented by merely rearranging the operator's work environment and/or by using appropriate occupational prescription lenses. Up until now however, operators are often unaware that such problems can be caused by improperly positioned computer equipment. Similarly, operators have not had the tools necessary to simply and effectively assess, and solve any problems in their work environments. Even optometrists and other health care providers often have a difficult time diagnosing computer-induced vision disorders. Even when the problem is correctly identified, these professionals typically lack the diagnostic information needed to make the appropriate recommendations.